Original XBOX motherboard and Hard Drive

I recently ran into a problem with my XBOX. I put a mod chip in it a long time ago and replaced with hard drive with a 120 gig one. Well, my mod chip broke and I need my original XBOX hard drive in order to put in a new mod chip. Problem is I lost it somehow. I was looking on ebay and people are selling XBOX motherboards with the matching hard drive. My question is are the motherboard and the hard drive the only 2 pieces of hardware that have to come from the same XBOX, or is there something else? If I get a motherboard and the matching hard drive will this work if I put them in my XBOX? Does anybody know this?

i guess it doesn't work like that because i already tried. I guess you have to start from ground zero with your original XBOX and unfortunately I don't have my original XBOX hard drive. What should I do now?

You don't need a new hard drive, as long as your new hard drive has all of the stuff you need (key,epprom,etc) and is running right now, and also i wouldn't buy a XBOX stock hard drive off of the internet, because you could be buying a banned hard drive and then you can't play xbl.